Journal of Neuroscience, Vol 5, 2143-2160, Copyright © 1985 by Society for Neuroscience
Small intensely fluorescent cells in culture: role of glucocorticoids and growth factors in their development and interconversions with other neural crest derivatives
AJ Doupe, PH Patterson and SC Landis
The neural crest gives rise to a number of adrenergic derivatives,
including sympathetic neurons and adrenal chromaffin cells, which contain
catecholamines (CAs) but differ in other morphological and functional
characteristics. Small intensely fluorescent (SIF) cells, which exist
primarily as a minority cell population in autonomic ganglia, are a third
cell type in the sympathoadrenal branch of the neural crest lineage. In
some respects these cells appear intermediate in phenotype between
sympathetic neurons and adrenal chromaffin cells. We established pure
dissociated cell cultures of SIF cells from rat superior cervical ganglia
(SCG) and used these to study the role of environmental factors in SIF cell
development and the relationship of these cells to the other cell types of
the sympathoadrenal lineage. When cells from neonatal rat SCG were grown
for 3 weeks in the presence of glucocorticoid and in the absence of nerve
growth factor (NGF), pure cultures of SIF cells developed. The properties
of the cells included (i) small cell size and the occasional presence of
short neurites, (ii) intense CA histofluorescence and immunoreactivity for
CA synthetic enzymes, (iii) synthesis and storage of CA from radioactive
precursors, and (iv) characteristic ultrastructure. The concentration of
the glucocorticoid and the presence or absence of non-neuronal cell factors
influenced which types of SIF cells developed. In micromolar glucocorticoid
most of the cells resembled adrenal chromaffin or type II SIF cells: they
displayed immunohistochemically detectable
phenylethanolamine-N-methyltransferase (PNMT), synthesized and stored
epinephrine, and contained large granular vesicles (100 to 300 nm). When
SCG cells were grown in 10(-8) M hormone, many fewer SIF cells developed
and a higher percentage of these lacked PNMT immunoreactivity, had
neurites, and contained vesicles of smaller mean diameter (70 to 130 nm),
similar to those of type I SIF cells in vivo. In the presence of
conditioned medium (medium conditioned by non- neuronal cells) as well as
glucocorticoid, virtually all of the cells morphologically resembled type I
SIF cells. In the absence of glucocorticoid, no SIF cells were ever
observed after 3 weeks in culture. By following the development of CA
histofluorescence and SIF cell ultrastructure in the cultures over time, we
demonstrated that SIF cells were not present in large numbers in these
cultures immediately after plating, but were induced from an apparently
undifferentiated precursor by the hormonal environment, whereas most of the
principal neurons died.(ABSTRACT TRUNCATED AT 400 WORDS)
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